网卡对象 绑定IP地址 然后向网卡对象写入数据 数据中将包含dst和src

tcpip/tcpip.go

@@ -1,8 +1,11 @@
 package tcpip
 
 import (
+	"errors"
 	"fmt"
+	"reflect"
 	"strings"
+	"sync/atomic"
 )
 
 type Error struct {
@@ -55,6 +58,12 @@ var (
 	ErrNoBufferSpace         = &Error{msg: "no buffer space available"}
 )
 
+// Errors related to Subnet
+var (
+	errSubnetLengthMismatch = errors.New("subnet length of address and mask differ")
+	errSubnetAddressMasked  = errors.New("subnet address has bits set outside the mask")
+)
+
 // Clock 提供当前的时间戳
 type Clock interface {
 	NowNanoseconds() int64
@@ -83,6 +92,70 @@ type Subnet struct {
 	mask    AddressMask
 }
 
+// NewSubnet creates a new Subnet, checking that the address and mask are the same length.
+func NewSubnet(a Address, m AddressMask) (Subnet, error) {
+	if len(a) != len(m) {
+		return Subnet{}, errSubnetLengthMismatch
+	}
+	for i := 0; i < len(a); i++ {
+		if a[i]&^m[i] != 0 {
+			return Subnet{}, errSubnetAddressMasked
+		}
+	}
+	return Subnet{a, m}, nil
+}
+
+// Contains returns true iff the address is of the same length and matches the
+// subnet address and mask.
+func (s *Subnet) Contains(a Address) bool {
+	if len(a) != len(s.address) {
+		return false
+	}
+	for i := 0; i < len(a); i++ {
+		if a[i]&s.mask[i] != s.address[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// ID returns the subnet ID.
+func (s *Subnet) ID() Address {
+	return s.address
+}
+
+// Bits returns the number of ones (network bits) and zeros (host bits) in the
+// subnet mask.
+func (s *Subnet) Bits() (ones int, zeros int) {
+	for _, b := range []byte(s.mask) {
+		for i := uint(0); i < 8; i++ {
+			if b&(1<<i) == 0 {
+				zeros++
+			} else {
+				ones++
+			}
+		}
+	}
+	return
+}
+
+// Prefix returns the number of bits before the first host bit.
+func (s *Subnet) Prefix() int {
+	for i, b := range []byte(s.mask) {
+		for j := 7; j >= 0; j-- {
+			if b&(1<<uint(j)) == 0 {
+				return i*8 + 7 - j
+			}
+		}
+	}
+	return len(s.mask) * 8
+}
+
+// Mask returns the subnet mask.
+func (s *Subnet) Mask() AddressMask {
+	return s.mask
+}
+
 // LinkAddress 是一个字节切片，转换为表示链接地址的字符串。
 // 它通常是一个 6 字节的 MAC 地址。
 type LinkAddress string // MAC地址
@@ -104,11 +177,96 @@ type Route struct {
 
 // Stats 包含了网络栈的统计信息
 type Stats struct {
-	// TODO 需要添加
+	// TODO 需要解读
+	// UnknownProtocolRcvdPackets is the number of packets received by the
+	// stack that were for an unknown or unsupported protocol.
+	UnknownProtocolRcvdPackets *StatCounter
+
+	// MalformedRcvPackets is the number of packets received by the stack
+	// that were deemed malformed.
+	MalformedRcvdPackets *StatCounter
+
+	// DroppedPackets is the number of packets dropped due to full queues.
+	DroppedPackets *StatCounter
+
+	// IP breaks out IP-specific stats (both v4 and v6).
+	IP IPStats
+
+	// TCP breaks out TCP-specific stats.
+	TCP TCPStats
+
+	// UDP breaks out UDP-specific stats.
+	UDP UDPStats
+}
+
+// A StatCounter keeps track of a statistic.
+type StatCounter struct {
+	count uint64
+}
+
+// Increment adds one to the counter.
+func (s *StatCounter) Increment() {
+	s.IncrementBy(1)
+}
+
+// Value returns the current value of the counter.
+func (s *StatCounter) Value() uint64 {
+	return atomic.LoadUint64(&s.count)
+}
+
+// IncrementBy increments the counter by v.
+func (s *StatCounter) IncrementBy(v uint64) {
+	atomic.AddUint64(&s.count, v)
+}
+
+type IPStats struct {
+	// PacketsReceived is the total number of IP packets received from the link
+	// layer in nic.DeliverNetworkPacket.
+	PacketsReceived *StatCounter
+
+	// InvalidAddressesReceived is the total number of IP packets received
+	// with an unknown or invalid destination address.
+	InvalidAddressesReceived *StatCounter
+
+	// PacketsDelivered is the total number of incoming IP packets that
+	// are successfully delivered to the transport layer via HandlePacket.
+	PacketsDelivered *StatCounter
+
+	// PacketsSent is the total number of IP packets sent via WritePacket.
+	PacketsSent *StatCounter
+
+	// OutgoingPacketErrors is the total number of IP packets which failed
+	// to write to a link-layer endpoint.
+	OutgoingPacketErrors *StatCounter
+}
+
+type TCPStats struct{}
+
+type UDPStats struct{}
+
+func fillIn(v reflect.Value) {
+	for i := 0; i < v.NumField(); i++ {
+		v := v.Field(i)
+		switch v.Kind() {
+		case reflect.Ptr:
+			if s, ok := v.Addr().Interface().(**StatCounter); ok {
+				if *s == nil {
+					*s = &StatCounter{}
+				}
+			}
+		case reflect.Struct:
+			fillIn(v)
+		}
+	}
+}
+
+// FillIn returns a copy of s with nil fields initialized to new StatCounters.
+func (s Stats) FillIn() Stats {
+	fillIn(reflect.ValueOf(&s).Elem())
+	return s
 }
 
 func (a Address) String() string {
-	fmt.Println(string(a), len(a))
 	switch len(a) {
 	case 4:
 		return fmt.Sprintf("%d.%d.%d.%d", int(a[0]), int(a[1]), int(a[2]), int(a[3]))